Ty: A fast Python type checker and language server

#1

Post by arathore » Wed, May 07, 2025, 5:32 PM UTC

Ty: A fast Python type checker and language server
github.com

Re: Ty: A fast Python type checker and language server

#2

Post by tmvphil » Wed, May 07, 2025, 5:47 PM UTC

Just compared the time to check on a fairly large project:

- mypy (warm cache) 18s

- ty: 0.5s (and found 3500 errors)

They've done it again.

Re: Ty: A fast Python type checker and language server

#3

Post by mil22 » Wed, May 07, 2025, 5:59 PM UTC

tmvphil wrote: post #2

Just compared the time to check on a fairly large project: - mypy (warm cache) 18s - ty: 0.5s (and found 3500 errors) They've done it again.

Great, but how does it compare to Pyright on the utility / performance curve? Pyright is mature and already very fast.

https://github.com/microsoft/pyright

Re: Ty: A fast Python type checker and language server

#4

Post by Handprint4469 » Wed, May 07, 2025, 6:08 PM UTC

If you have uv installed, you can test it without installing by running:

  uvx ty check

Re: Ty: A fast Python type checker and language server

#5

Post by js2 » Wed, May 07, 2025, 6:11 PM UTC

tmvphil wrote: post #2

Just compared the time to check on a fairly large project: - mypy (warm cache) 18s - ty: 0.5s (and found 3500 errors) They've done it again.

I have no doubt that it will be faster than mypy, but:

> This project is still in development and is not ready for production use.

Re: Ty: A fast Python type checker and language server

#6

Post by throwaway63467 » Wed, May 07, 2025, 6:15 PM UTC

I was wondering when someone would write a type checker in Rust, seemed like an obvious thing to do given how slow mypy is.

Re: Ty: A fast Python type checker and language server

#7

Post by nine_k » Wed, May 07, 2025, 6:18 PM UTC

mil22 wrote: post #3

tmvphil wrote: post #2

Just compared the time to check on a fairly large project: - mypy (warm cache) 18s - ty: 0.5s (and found 3500 errors) They've done it again.

Great, but how does it compare to Pyright on the utility / performance curve? Pyright is mature and already very fast. https://github.com/microsoft/pyright

Pyright is good, but it's quite a memory hog. (Yes, I have plenty of RAM on my machine. No, it has other uses during development, too.)

Re: Ty: A fast Python type checker and language server

#8

Post by drcongo » Wed, May 07, 2025, 6:23 PM UTC

I've been looking forward to this for what seems like an age.

Re: Ty: A fast Python type checker and language server

#9

Post by codydkdc » Wed, May 07, 2025, 6:27 PM UTC

drcongo wrote: post #8

I've been looking forward to this for what seems like an age.

how long is an age?

Re: Ty: A fast Python type checker and language server

#10

Post by nickagliano » Wed, May 07, 2025, 6:27 PM UTC

Interesting to see astral come out with this right around facebook’s release of “Pyrefly, a faster Python type checker written in Rust”.

Not making any sort of ethical statement, just interesting that rust keeps eating the python and JS tooling worlds.